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// SPDX-License-Identifier: GPL-2.0+
/*
* Generate a table for CRC-32C calculation.
*
* Copyright (C) 2018 Google LLC
*
* Written by Eric Biggers.
*/
#include <stdint.h>
#include <stdio.h>
/*
* This is the CRC-32C (Castagnoli) polynomial: x^32+x^28+x^27+x^26+x^25+x^23+
* x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+x^8+x^6+x^0, with the polynomial
* coefficients mapped to bits using the "little endian" convention.
*/
#define CRC32C_POLY_LE 0x82F63B78
static uint32_t crc32c_update_bit(uint32_t remainder, uint8_t bit)
{
return (remainder >> 1) ^
(((remainder ^ bit) & 1) ? CRC32C_POLY_LE : 0);
}
static uint32_t crc32c_update_byte(uint32_t remainder, uint8_t byte)
{
int bit;
for (bit = 0; bit < 8; bit++, byte >>= 1)
remainder = crc32c_update_bit(remainder, byte & 1);
return remainder;
}
static uint32_t crc32c_table[256];
int main(void)
{
int i, j;
for (i = 0; i < 256; i++)
crc32c_table[i] = crc32c_update_byte(0, i);
printf("/*\n");
printf(" * crc32c_table.h - data table to accelerate CRC-32C computation\n");
printf(" *\n");
printf(" * This file was automatically generated by scripts/gen_crc32c_table.c\n");
printf(" */\n");
printf("\n");
printf("static const u32 crc32c_table[] = {\n");
for (i = 0; i < 64; i++) {
printf("\t");
for (j = 0; j < 4; j++) {
printf("0x%08x,", crc32c_table[i * 4 + j]);
if (j != 3)
printf(" ");
}
printf("\n");
}
printf("};\n");
return 0;
}
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